Dietary blueberry improves cognition among older adults in a randomized, double-blind, placebo-controlled trial

Authors: Miller, Marshall; HAMILTON, DEREK - University Of New Mexico; JOSEPH, JAMES - Former ARS Employee; Shukitt-Hale, Barbara

Submitted to: European Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2017
Publication Date: 3/13/2017
Citation: Miller, M.G., Hamilton, D.A., Joseph, J.A., Shukitt Hale, B. 2017. Dietary blueberry improves cognition among older adults in a randomized, double-blind, placebo-controlled trial. European Journal of Nutrition. 57:1169-1180. https://doi.org/10.1007/s00394-017-1400-8.
DOI: https://doi.org/10.1007/s00394-017-1400-8

Interpretive Summary: As populations shift to include a larger proportion of older adults, the necessity of research targeting older populations is becoming increasingly apparent. Changes in motor coordination during ‘normal’ aging, in animals and humans, include decrements in balance and locomotion. Parallel to alterations in motor function, changes in cognitive function in aging include decrements in learning, memory, navigational ability, and other mental functions. Dietary interventions with blueberry have been associated with positive outcomes in cell and rodent models of aging. In this study, men and women between the ages of 60 and 75 years were recruited into a trial in which they were randomly placed into one of two groups: a group that consumed freeze-dried blueberry (24g/d, equivalent to 1 cup of fresh blueberries) or a group that consumed a blueberry-flavored placebo for 90 days; since the supplement packets were coded, neither participants nor researchers were aware of the group to which they belonged until after the completion of the analyses. Participants’ balance, gait, and cognition were tested at the start and again at 45 and 90 days of intervention. Participants in the blueberry group showed significantly fewer errors in a verbal learning test and increased mental flexibility on a task- switching test, relative to the placebo group. These findings show that the addition of easily achievable quantities of blueberry to the diets of older adults can improve some aspects of cognition.

Technical Abstract: As populations shift to include a larger proportion of older adults, the necessity of research targeting older populations is becoming increasingly apparent. Changes in motor coordination during ‘normal’ aging, in animals and humans, include decrements in balance and locomotion. Parallel to alterations in motor function, changes in cognitive function in aging include decrements in learning, memory, spatial cognition, and executive function. Dietary interventions with blueberry have been associated with positive outcomes in cell and rodent models of aging. In this study, men and women between the ages of 60 and 75 years were recruited into a randomized, double-blind, placebo-controlled trial in which they consumed freeze-dried blueberry (24g/d, equivalent to 1 cup of fresh blueberries) or a blueberry placebo for 90 days. Participants’ balance, gait, and cognition were tested at baseline and again at 45 and 90 days of intervention. Participants in the blueberry group showed significantly fewer repetition errors in the California Verbal Learning test and reduced switch cost on a task-switching test, relative to controls. These findings show that the addition of easily achievable quantities of blueberry to the diets of older adults can improve some aspects of cognition.